One of the goals in the design of writing instruments is to provide a device which, when extended for use, is of sufficient length to be held comfortably in the hand, but which may also be retracted into a compact configuration for storage. Another important consideration is the need to isolate the marking element from contact with clothing, furniture and other articles when the element is not in use.
A common approach to the problem of isolating the writing or marking element is the familiar cap and barrel combination wherein a cap is placed over the end of the barrel which houses the element when it is not in use. Hereafter, the term "writing element" is used to refer either to a writing or marking element. The cap may then be removed and stored on the rear of the barrel when the implement is in use. Although this arrangement serves to isolate the writing element, there is generally no advantage offered in terms of reducing the size of the implement for storage. Further, the cap is often lost after it has been separated from the barrel.
Another common arrangement is a push top mechanism wherein a writing element is received in a tubular housing, the element having a compressible spring disposed about the writing end to provide a biasing force between the element and the writing tip end of the housing. The opposite end of the element typically engages a cam mechanism within the housing which moves the element between its extended and retracted positions. While these mechanisms serve to protect the writing element, they provide very little reduction in the overall size of the implement for purposes of storage. Furthermore, a major disadvantage of these mechanisms is that they are generally complex and have a large number of moving parts.
The present invention represents an improvement over the aforementioned prior art devices by providing a writing implement which allows the writing element to be extended to a convenient position for use or completely retracted into a compact, convenient package and which is simply constructed with a minimum of moving parts.